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Isotropic probe? - RF Cafe Forums

Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views. It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if you would like to post something on RF Cafe's Facebook page, please do.

Below are all of the forum threads, including all the responses to the original posts.


 Post subject: Isotropic probe?
Posted: Mon Jan 29, 2007 4:43 pm 
 
Captain
User avatar

Joined: Fri Apr 07, 2006 6:10 pm
Posts: 18
I thought an isotropic antenna is mythical. What is an isotropic probe?

As referred by the following, site: http://www.emctd.com/


 
   
 
 Post subject:
Posted: Tue Jan 30, 2007 7:22 am 
 
General
User avatar

Joined: Fri Feb 17, 2006 12:07 pm
Posts: 218
Location: London UK
It's possible to synthesize an approximation to an isotropic antenna that is close enough for most measurement purposes over a limited frequency range.
Three bolometers mutually at right angles is one solution that springs to mind. Obviously this will be very insensitive, but it is a three axis RF detector with broad bandwidth, and so fulfills most criteria for an isotropic receiving antenna. But then, it is not a reciprocal device, so cannot be used for transmission.
If you extend this concept to a set of three loops or patches, each having good cross-polar isolation in its own plane, and combine them in a 3-way combiner, you perhaps have a narrow band isotropic radiator and detector.
None of these ideas meets the true full-spectrum reciprocal well-matched antenna necessary to be an isotrpoic radiator. To this extent therefore, the true isotropic radiator is a theoretical concept.


 
   
 
 Post subject: Re: Isotropic probe?
Posted: Sun Feb 04, 2007 8:50 am 
 
Lieutenant

Joined: Sat Feb 03, 2007 4:13 pm
Posts: 3
Mr.Whatever wrote:
I thought an isotropic antenna is mythical. What is an isotropic probe?
As referred by the following, site: http://www.emctd.com/


Isotropic antenna in theory is a Huygens source with cardiod antenna diagram and directivity 4.77 dBi. It may be two dipoles electrical and magnetic. Magnetic dipole may be a loop or slot.




Posted  11/12/2012
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